TITLE:   GCN CIRCULAR
NUMBER:  33019
SUBJECT: GRB 221202B: Detection by VZLUSAT-2
DATE:    22/12/04 13:08:54 GMT
FROM:    Jakub Ripa at Masaryk University  <245487@mail.muni.cz>

J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory),  N. Werner (Masaryk 
U.), M. Ohno (Hiroshima U.),  L. Meszaros, B. Csak (Konkoly 
Observatory), H. Takahashi (Hiroshima U.), F. Munz , M. Topinka, F. 
Hroch, M. Dafcikova, N. Husarikova, J.-P. Breuer (Masaryk U.), J. Hudec, 
J. Kapus, M. Frajt, M. Rezenov (Spacemanic s.r.o), R. Laszlo 
(Needronix), G. Galgoczi (Wigner Research Center/Eotvos U.), N. Uchida 
(ISAS/JAXA), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. 
Hirose, H. Matake (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe 
(Rikkyo U.), L. L. Kiss (Konkoly Observatory),  T. Mizuno (Hiroshima 
U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), K. Torigoe 
(Hiroshima U.), P. Svoboda, V. Daniel, J. Dudas, M. Junas, J. Gromes 
(VZLU), I. Vertat (FEL ZCU)  -- the VZLUSAT-2/GRB payload collaboration.

A long-duration GRB 221202B (Fermi/GBM detection: The Fermi GBM team, 
GCN Circ. 33006; Konus-Wind detection trigger time at 2022-12-02 
21:41:58.66 UT; INTEGRAL/SPI-ACS detection peak at ~2022-12-02 21:42:00 
UT) was marginally detected by the GRB detector on board of the 
VZLUSAT-2 3U CubeSat (https://www.vzlusat2.cz/en/).

The data acquisition was performed by GRB detector unit no. 1 and the 
marginal detection shows the peak time 2022-12-02 21:42:03 UTC. The T90 
duration was measured to be 20 s with the light curve resolution of 1 s. 
The significance during T90 reaches 5.4 sigma.

The light curve obtained by VZLUSAT-2 is available here:
https://vzlusat2.konkoly.hu/static/share/GRB221202B_GCN_VZLUSAT2.pdf

GRB detectors on VZLUSAT-2 are a demonstration payload for a future 
CubeSats constellation (Werner et al. Proc. SPIE 2018). Two GRB modules 
of VZLUSAT-2 are placed in a perpendicular manner and each consists of a 
75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the 
energy range from ~30 keV to ~1000 keV. VZLUSAT-2 was launched on 2022 
January 13 from Cape Canaveral.